Sony STR-313L FM-AM Program Receiver

General Specifications

Power Requirements: 240V ac, 50Hz (UK model); 120V, 220V or 240V ac adjustable, 50Hz (AEP model)

Power Consumption: 210W (UK model); 180W (AEP model)

Dimensions: Approx. 410(w)x145(h)x310(d)mm (16"w x 5³/4"h x 12³/8"d) including projecting parts and controls

Weight: Approx. 7.6kg, 16 lb 13 oz (net); Approx. 8.8kg, 19 lb 7 oz (in shipping carton)

FM Section

Frequency Range: 87.5-108MHz

Antenna: 300 Ω balanced; 75 Ω unbalanced

Intermediate Frequency: 10.7MHz

Sensitivity at 50dB Quieting: 3.5µV (10.7dB) (MONO); 45µV (33dB) (STEREO)

Sensitivity at 46dB Quieting: 4µV (12dB) (MONO); 50µV (34dB) (STEREO)

Usable Sensitivity: 1.8µV (5dB), IHF; 1.6µV (4dB), S/N=26dB

S/N Ratio: 75dB (MONO); 70dB (STEREO)

Harmonic Distortion: At 100Hz: 0.2% (MONO), 0.3% (STEREO); At 1kHz: 0.2% (MONO), 0.3% (STEREO); At 10kHz: 0.3% (MONO), 0.5% (STEREO)

IM Distortion: 0.2% (MONO); 0.3% (STEREO)

Separation: 30dB at 100Hz; 45dB at 1kHz; 35dB at 10kHz

Frequency Response: 40-12,500HzdB; 30-15,000HzdB

AM Section (SW/MW/LW)

Frequency Range: SW: 5.8-15.8MHz; MW: 530-1,605kHz; LW: 150-350kHz

Antenna: SW/MW: External antenna terminal, Attached antenna wire; LW: Built-in Ferrite-rod antenna, External antenna terminal

Intermediate Frequency: 468kHz

Usable Sensitivity: SW: 30µV (29.5dB), external antenna (10MHz); MW: 100µV (40dB), external antenna (1,000kHz); LW: 500µV/m (53.8dB/m), built-in antenna; 100µV (40dB), external antenna (230kHz)

S/N Ratio: SW/MW: 52dB (5mV); LW: 52dB (50mV/m)

Harmonic Distortion: SW/MW: 0.3% (5mV, 400Hz); LW: 0.3% (50mV/m, 400Hz)

Selectivity: 28dB (9kHz); 30dB (10kHz)

Audio Amplifier Section

Continuous RMS Power Output: Less than 0.5% THD, both channels driven simultaneously at 20-20,000Hz: 25W+25W (8 Ω); At 1kHz: 27W+27W (8 Ω); According to DIN 45500: 25W+25W (8 Ω); 25W+25W (4 Ω, less than 0.7% THD)

Dynamic Power Output: IHF constant power supply method: 90W (8 Ω)

Power Bandwidth: 10-40,000Hz, IHF

Damping Factor: 20 at 1kHz (8 Ω)

Harmonic Distortion: Less than 0.5% at rated output (8 Ω); Less than 0.7% at rated output (4 Ω); Less than 0.2% at 1W output (8 Ω); Less than 0.3% at 1W output (4 Ω)

IM Distortion: Less than 0.5% at rated output; Less than 0.2% at 1W output

Residual Noise: Less than 0.08µW (at 8 Ω)

PHONO Frequency Response: RIAA equalization curve ±1dB

TAPE Frequency Response: 10-50,000 Hz +1dB -3dB

Inputs:

Measured with rated output power into 8 Ω loads (both channels driven simultaneously) at 1kHz.

Outputs:

Headphones: Accepts all low or high impedance headphones.

Speaker: 4-16 Ω speakers are suitable.

Tone Controls: BASS ±8dB at 100Hz; TREBLE ±8dB at 10kHz

Loudness Control: +8dB at 100Hz; +3dB at 10kHz

Model Identification

AEP Model

SONY FM-AM PROGRAM RECEIVER, MODEL NO. STR-313L

FREQ RANGE: FM 87.5-108 MHz, SW 5.8-15.8 MHz, MW 530-1605 KHz, LW 150-350 KHz

IF: FM 10.7 MHz, AM 468 KHz

AC: 220 V ~ 50 Hz 180 W

MADE IN

SERIAL NO.

UK Model

SONY FM-AM PROGRAM RECEIVER, MODEL NO. STR-313L

FREQ RANGE: FM 87.5-108 MHz, SW 5.8-15.8 MHz, MW 530-1605 KHz, LW 150-350 KHz

IF: FM 10.7 MHz, AM 468 KHz

AC: 240 V ~ 50 Hz 210 W

MADE IN

SERIAL NO.

Section 1: Outline - Block Diagram

The block diagram illustrates the signal flow through the Sony STR-313L receiver, starting from the antenna input through various stages like the front-end block, FM IF amplifier, detector, and audio amplifier, to the speaker output.

Diagram showing the block structure of the FM-AM Program Receiver.

Section 1: Circuit Description

Program Sensor

The program sensor uses optical detection to automatically select FM or LW stations when the band selector and function switches are set correctly and the pointer aligns with a station marker.

• FM Station Marker Alignment: When the pointer aligns with the FM marker, IC401 (Photo Interrupter) is activated, leading to the FM circuit operation and the FM indicator lamp (PL401) lighting up.
• LW Station Marker Alignment: When the pointer aligns with the LW marker, IC401 is not intercepted, and IC402 is intercepted by the LW marker, activating the LW circuit and the LW indicator lamp (PL402).
• Simultaneous Alignment: When both FM and LW markers align, the FM station signal is received, and the LW indicator lamp remains off.

Q202 and Q401

Q401 enhances the response time of the indicator lamps (PL401, PL402) during tuning. Q202 acts as a high-speed muting switch, activated or deactivated based on the tuned station signal.

IC201 (CX168) and IC202 (CX178)

These two bipolar-linear ICs integrate multiple functions for tuner use. They provide high performance in FM reception, including a 90dB FM muting attenuation. The AM circuit also benefits from a muting circuit, ensuring fine tone quality and sensitivity. Additional functions include FM/AM continuous station selection, signal-strength meter output, FM/AM muting output switching, and enforced AGC for FM reception.

CX168 Main Functions:

• Muting Gate
• Regulator
• Muting Canceler Circuit
• Pop-noise Canceler
• Hysteresis Circuit
• FM IF Amplifier
• Quadrature detector
• Signal-strength Meter Output
• Muting Signal Output
• AFC Output for Converter
• Multipath Signal Output
• Bandpass Control Circuit
• RF Attenuator (AM)
• Mixer (AM)
• Oscillator (AM)
• IF Amplifier and AGC (AM)
• AM Detector (AM)
• Signal-Strength Meter Output (AM)
• Signal Generator for AM Muting (AM)
• Regulator Output (General)
• FM/AM Switching (General)

CX178 Main Functions:

• FM Stereo Demodulator
• Phase Detector
• Stereo Indicating Circuit
• VCO
• VCO ON/OFF Circuit
• Regulator (General)
• FM/AM Switching (General)
• Regulator Output (General)

Photo Interrupter (IC401, 402)

Terminals (1) and (2) of the photo interrupter serve as the light-emitting diode. Terminals (3) and (4) function as the photo detector. When the photo detector receives light (Fig. 3), the impedance between terminals (3) and (4) is low. When light is intercepted by a marker (Fig. 4), the impedance becomes high.

Section 2: Disassembly

Follow the numerical order for disassembly procedures.

Top Cover Removal

Remove the top cover screws.

Bottom Plate Removal

Remove screws (BVTT3x6) securing the bottom plate.

Front Glass Removal

Remove screws (TA, B3x6) and glass retainers to detach the front glass.

Front Panel Removal

Pull out the knobs. Remove screws (BV3x6, TA, B3x6) and the set screw (2mm) to remove the front panel.

IC Replacement

Unscrew the heat sink and IC bracket. Unsolder the pins of IC601. Remove screws (BVTT3x6) to detach the main circuit board.

Section 3: Adjustments

SW, MW Section

Setting: FUNCTION switch: (Band Selector) SW, MW

MW Frequency Coverage Adjustment: Adjust for maximum reading on VOM using L305 and CT305.

MW Tracking Adjustment: Adjust for maximum reading on VOM using CT302 and L302.

SW Frequency Coverage Adjustment: Adjust for maximum reading on VOM using L304 and CT304.

SW Tracking Adjustment: Adjust for maximum reading on VOM using CT301 and L301.

Note: Repeat adjustments several times for final calibration using trimmer capacitors.

LW Section

Setting: FUNCTION switch: (Band Selector) LW; ANTENNA LW switch: BUILT IN

LW Tracking Adjustment: Adjust for maximum reading on VOM using CT303 and L801.

LW Frequency Coverage Adjustment: Adjust for maximum reading on VOM using L306 and CT306.

LW EXT Antenna Coil Adjustment: Set ANTENNA LW switch to EXT. Tune to 170 kHz and adjust L303 for maximum VOM reading.

Note: Repeat adjustments several times for final calibration using trimmer capacitors.

FM Section

Setting: FUNCTION switch: FM

FM Frequency Coverage Adjustment: Adjust for maximum reading on VOM using L3 and TC3 for 87.1 MHz (87.5 MHz) and 108.5 MHz (108 MHz).

FM Tracking Adjustment: Adjust for maximum reading on VOM using L2, TC2, and TC1 for 87.1 MHz (87.5 MHz) and 108.5 MHz (108 MHz).

Note: Repeat adjustments several times for final calibration using trimmer capacitors.

FM Discriminator Alignment 1 & 2

Alignment 1: Tune the set and turn the primary side core of IFT201 for a null-point reading on the FM TUNING meter.

Alignment 2: Set MODE switch to MONO. Turn the secondary side core of IFT201 for a minimum distortion reading on the distortion meter.

FM Stereo Separation Adjustment

Adjust RT202 for minimum reading in L-CH and R-CH connections to achieve equal stereo separation.

FM IF Alignment

Tune the set to 98 MHz and adjust IFT1 for a maximum reading on the VTVM.

MPX Adjustment

Regular Method: Tune to 98 MHz, adjust RT201 for 76 kHz ±100Hz on the frequency counter.

Simple Method: Tune to an FM stereo broadcast signal. Adjust RT201 to the center of the STEREO lamp's lighting-up range.

Section 4: Diagrams

IC Block Diagram

Diagrams showing the internal blocks of IC201 (CX168), IC202 (CX178), and IC601 (S11125HD).

Mounting Diagram - Conductor Side

Illustrates the mounting positions of semiconductors and ICs on the conductor side of the circuit board. Includes replacement semiconductor information.

Replacement Semiconductors: Lists specific part numbers for transistors and diodes.

Note: Indicates side identified with part number; part mounted on the conductor side; color code of sleeving.

Section 5: Parts List

Electrical Parts List

Detailed list of electrical components including semiconductors, transformers, capacitors, coils, diodes, switches, and miscellaneous items with their respective part numbers and descriptions.

Accessories and Packing Materials

List of included accessories such as antenna, bags, cartons, and manuals.

Section 6: Hardware Nomenclature

Screws

Provides a nomenclature for various screw types, including self-tapping screws, set screws, nuts, washers, and retaining rings, with their reference designations and descriptions.

1/4 Watt Carbon Resistors

A comprehensive list of 1/4 Watt carbon resistors with their resistance values and corresponding part numbers.

Safety Related Component Warning

Components identified by shading and specific marks on schematic diagrams, exploded views, and parts lists are critical for safe operation. These components must be replaced with genuine SONY parts.

Additional Information

For more Hi-Fi manuals and set-up information, please visit www.hifiengine.com.